[4SLASH6]

70 gto,fuel gauge reads full,key on key off...battery disconnected also shows full??? where should I start to troubleshoot this? this is the state it was in when I purchased vehicle,orange ground from sending unit grounded,also brown wire hooked to terminal on top of sending unit...??

[4SLASH6]

70 gto,fuel gauge reads full,key on key off...battery disconnected also shows full??? where should I start to troubleshoot this? this is the state it was in when I purchased vehicle,orange ground from sending unit grounded,also brown wire hooked to terminal on top of sending unit...??

[RAM YAK II]

If I remember right, you've lost your ground. Find the wire that goes from the sending unit to the body. Remove the screw and clean the area where it attaches to the body and re-attach the wire. Use a star washer under the ring terminal if you have one. They can be picked up at your local hardware.

[4SLASH6]

don"t think that is the problem,just installed new trunk floor, have ground wire grounded to fresh steel.....problem I think is in gauge itself since it reads full all the time ,even with batt. disconnected....going to climb under dash & have a look today, maybe if I tap it lightly it will fall back to "E" ...( do you need a boilers license to do that??)

[BLOWBAYOU]

THERE SHOULD BE A CONNECTOR IN YOUR TRUNK THAT CONNECTS TO THE FUEL TANK SENDING UNIT.
UNPLUG THE CONNECTOR AND WITH THE KEY IN THE ON POSITION GROUND THE SIDE OF THE CONNECTOR THAT GOES TO THE DASH.
A WORKING GAS GAUGE SHOULD THEN GO DIRECTLY TO EMPTY.
IF NOT, THEN YOUR PROBLEM COULD BE A BAD PRINTED CIRCUIT, AN OPEN {BROKEN} FEED WIRE OR A BAD DASH GAUGE.
IF IT DOES GO TO EMPTY, YOU HAVE A GROUND PROBLEM AT THE SENDING UNIT OR A BAD FUEL SENDING UNIT IN THE TANK.

[4SLASH6]

okay, now we are getting somewhere.....after grounding harness wire inside trunk,with key on,gauge went to empty. next up, I will try a different ground area for sending wire,and if that dont work looks like I will have to drop the tank and pull the unit. thanks for the help guy"s

[4SLASH6]

ground secured,no diff.so I pulled the tank,wiggled wire (ground) at sending unit,bingo! gauge working....pulled sending unit out,cleaned,attached new ground wire to unit...old wire had lost its color inside,as I peeled back insulation entire length was discolored. nice call on ground ram-yak!

[Kirt H Ulfers]

Had same problem in my 65 GTO. Did the same diagnostic tests. Eventually dropped tank and found that metal strap going into the resistor in the sending unit had broken loose. Simple and inexpensive fix to replace sending unit while the tank was down. Problem fixed.